How can I specify an unordered Execution Block using the TPL Dataflow Library?

I want to set up a

TransformBlock

that processes its item in parallel. Thus, I'm setting

ExecutionDataflowBlockOptions.MaxDegreeOfParallelism

to > 1. I don't care about the order of the messages but the documentation says:

When you specify a maximum degree of parallelism that is larger than 1, multiple messages are processed simultaneously, and therefore, messages might not be processed in the order in which they are received. The order in which the messages are output from the block will, however, be correctly ordered.

Does "correctly ordered" mean that if there is one message in the queue that needs long processing time, further messages are not output until this one message is processed?

And if so, how can I specify an Execution Block (for example a

TransformBlock

) that does not care about the ordering? Or do I have to specify at the consumption end that I don't care about ordering?

This way, once an item is processed by the ActionBlock, it's immediately moved to the BufferBlock, which means ordering is not maintained.

One issue with this code is that it doesn't observe the set BoundedCapacity well: in effect, the capacity of this block is twice the capacity set in options (because each of the two blocks has a separate capacity).

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